1. Field
The field is production and processing of biofuels.
2. Prior Art—Non-Patent Literature Documents
The following is a list of some prior art that presently appears relevant:    Begg, J. and Gaskin, T., National Toxicology Group, http://www.inchem.org/documents/pims/plant/jcurc.htm, June, 1994    Aregheore, E. M., Becker, K., and Makkar, H. P. S., “Detoxification of a toxic variety of Jatropha curcas using heat and chemical treatments, and preliminary nutritional evaluation with rats”, S. Pac. J. Nat. Sci., 2003, Vol. 21, pp. 50-56.    Environmental Control and Research Program, National Institutes of Health, Division of Occupational Health and Safety, “Phorbol esters” Safety Data Sheet”, May 1984.
Discussion
Jatropha is a genus of approximately 175 succulents that are perennial plants of the spurge family (Euphorbiaceae) and are native to Central and South America. “Jatropha” is derived from iatros (physician) and trophe (nutrition), so the plant is known by the common name “physic nut”. Its seeds are used to produce Jatropha oil, which is burned in diesel engines, but it has other uses. The plants are resistant to drought and pests but they have poisonous components. Some varieties are deciduous, such as Jatropha curcas Linnaeus (JCL)
JCL is a shrub or tree that now grows pantropically. Begg and Gaskin, supra, report that the chemical composition of the seeds cultivated in common locations typically show a protein content of 18.0% by weight, fat 38.0%, and carbohydrates 17.0%. Biodiesel from JCL seeds is fast becoming recognized as a potential source of alternative fuel to meet the rising demands of countries around the world. The fuel contains no sulfur and is thus a clean, low-emission fuel. JCL has the potential to serve as fuel to power a vast array of energy needs from wheeled transportation, combined heat and power (CHP) plants, and even cooking stoves. In addition, after diesel oil is extracted, a block or cake of the plant fibers is left that can be pressed to form an oil-less cake that provides a useful agricultural material. The cake has mineral contents of nitrogen (6%), phosphorus (2.75%), and potassium (0.94%); this mineral content is similar to that of chicken manure and can be used for soil enrichment.
In addition to nutrients, the press cake contains toxic substances that give the plant its disease and pest resistance. There are two principal toxins: lectins, also known as curcin, and phorbol esters. In the past, these toxins prevented use of the press cake in human and animal nutrition.
Lectins are carbohydrate-binding proteins or glycoproteins which have specific coagulation properties. These can be broken down by heat treatments. Aregheore et al., supra, report that heat treatment inactivates lectin, reducing toxicity to tolerable levels for human consumption.
Phorbol esters are diterpenes that have tumor-promoting properties. Aregheore et al. report that the esters can be removed from the press cake by extraction using an alcohol such as ethanol. Depending upon the variety, JCL seeds contain between 0.03 and 3.3 mg of phorbol esters per gram of seeds. Neither the pressing of the seeds nor the usual prior-art processing of the oil, i.e., washing or treating with activated carbon, destroys these esters. However extraction reduces the esters to a tolerable level of 0.09 mg/g. Phorbol esters are nearly insoluble in water.
After detoxification by these two methods, humans can consume the JCL seeds and do so in some developing countries.
JCL seeds contain energy-bearing components: lipids within the seed cell structures can be collected and converted into oil used for the production of biodiesel according to procedures described elsewhere (see our above U.S. Pat. No. 8,043,496); carbohydrates in the cell structures can be converted into sugars and then ethanol, which is used first to scrub the press cake to be detoxified and then the same ethanol is used to process the oil to be biodiesel by procedures as described elsewhere (see our above U.S. Pat. No. 8,017,366). After removing the oil and the ethanol used in extraction of toxins, the protein meal is suitable for human consumption. The husks of JCL fruits amount up to 35% of the weight of the fruit and at harvest the dry husks can be directly used as a fuel.
When JCL is grown in hedges or in small farms in developing countries, the yield of fruit, i.e., JCL nuts and their husks, is about 1 kg/sq. meter/year, thereby limiting oil generation to a local enterprise. Collecting and processing the fruit can provide needed fuel, and can also inject money into the local economy. The added ability of producing a protein-rich meal for consumption enhances the potential of JCL as an economically viable feedstock.
Insofar as we are aware, there no transportable processing apparatus that can be delivered along a water course by ship or barge, by rail line, by road wheeled transportation, or by air to a location in proximity to the agricultural sites where JCL is grown.